I'm about to build a new personal blog/portfolio site (which will be written in ASP.NET), and I'm going to run it against a SQLite database. There are a few reasons for this:
The site will not be getting a lot
of traffic, and from what I've read,
SQLite is able to support quite a
lot of concurrent users for reading
anyway
I can back up all the content
easily, just by downloading the db
over FTP
I don't have to pay my hosting
company every month for a huge
SQL2008 database that I'm hardly
using
So, should I go for it, or is this a crazy idea?
I'm not so sure about #2 (what happens if SQLite makes changes to the file while the FTP program is reading it?) but other than that, there is no reason to prefer one DB over the other (unless one of those DBs just can't do what you need).
[EDIT] Use an online backup to create the file for FTP download. That will make sure the file content is intact.
Even better, add a page (with password) to your site which creates the file at the press of a button, so your browser can download it.
It's just fine for a low traffic site as long as it's mostly read traffic. If it were me, I'd use SQL Compact Edition instead (same benefits as Sqlite- single file, no server), just because I'm a LINQ-head and the LINQ providers are "in the box" for it, but Sqlite has a decent LINQ library and managed support as well. Make sure your hosting company allows unmanaged code, or that you use the managed port of Sqlite (don't know its current stability though).
SQLite can handle this easily - go for it.
You should check, but I think that the Express version of SQL 2008 is free of charge.
Anyway, I've been working with SQLite from .NET environment, and it works quite fine (but I haven't done any load test).
And if you're not decided yet, you still can use a LINQ provider which will allow you later to switch from one database to another without rewriting your SQL code (I think to DbLinq, for example).
If you plan to backup you database, you must ensure first that it is not used at the moment.
SQLite answer this for you:
http://sqlite.org/whentouse.html
low-medium volume = okay,
high volume = don't use it
in your case its a-ok to use sqlite
Generally, yes.
But you should be aware of the fact that SQLite does not support everything that you might be used to from a 'real' DBMS. E.g. there are no constraints like foreign keys, unique indexes and the like, and AFAIK some (more advanced) datatypes are not available.
You should check for the various limitations here and here. If you can get along with that there's no reason to not use SQLite.
A rule of thumb is that if the site can run on one server
then SQLite is sufficient. That is what the creator of
SQLite, D. Richard Hipp, said at approximately 13 min
30 secs into episode 26 of the FLOSS Weekly
podcast.
Direct audio link (MP3 file, 24 MB, 51 min 15 sec).
I'd say no. First off, I don't know who you are using for a provider, but with my provider (goDaddy), it's pretty cheap at $2.99 a month or so. I get 1 sql server db and 10 mysql dbs.
I don't know how much cheaper this can get.
Secondly, why risk it? Most provider plans include at least MySQL database. You can hook up with that.
In general, SQLite isn't meant for a high-traffic website, but it can do quite well on websites getting 100,000 hits/day or less. The SQLite org website gets more than 500,000 hits/day, and generates 2 million or more DB interactions/day ... all handled by SQLite.
Here are some things that will dramatically speed up SQLite's performance:
Index your tables
Use transactions for multiple commands instead of executing one at a time.
Learn about write-ahead logging
Do a Google search on each of the above with SQLite ... your DB performance will improve dramatically.
An SQLite DB can actually be faster than a MySQL, PostGRE, MS SQL Server DB, or other hosted server-based DBs for 2 reasons:
1). SQLite is usually stored on the same machine as the website, rather than a separate server machine, eliminating round trip network latency response times.
2.) For smaller read/write requests, the SQLite engine is executing far less code, which can also be faster.
For a smaller website, a smaller DB engine like SQLite could actually be faster and more efficient.
Are you using any SQL functionality? SUM, AVG, SORT BY, etc, if yes go use SQLite. If not, just use plain txt files to store your data. Also make sure that the database is outside the httpdocs folder or it is not web accessible.
Related
I am recently working with a relational database program that has been written in Excel VBA. Excel VBA was chosen as it is a default application on computers where I work and therefore everyone would be able to use the database.
As part of the database development the need has arisen to add some more tables which will only interact programmatically with the current database. In order to consider all my options I am contemplating separating this new data either as an SQLite or second excel file.
I keep changing my mind as to what would be the best route and would appreciate information from those who work with the programs.
The new database would need to perform normal database functions quickly and efficiently. Given this context what are the advantages/disadvantages of using SQLite compared with excel?
Excel is not a database! If you want to use the Office applications, use Access, it is designed for that.
If you want to use SQLite, bear in mind that there is no concurrency. So if PC1 writes to the database, and PC2 wants to do that too, the file is locked by PC1 and you will get an error on PC2.
My recommendation:
You can also install SQL Server Express, this is free, with a few terms (10 concurrent users & max 10GB db). And then store your data in your SQL server. Use Excel as an interface to collect data from the SQL Server in your Excel/VBA applications. This is a lot more scale-able then Access, let alone SQLite.
OR: If your organization doesn't allow installation of software or whatever reason, go for Access.
You can use SQLite if you have a single application on a single device. Think about mobile apps, they use SQLite for example. If you have two applications on a single device, the concurrency problem of SQLite comes around the corner. It is possible that both apps want to write at the same time, which will give you an error.
I have got a Bizspark account from Microsoft and they are providing a basic Azure account. I have been told that it can run PHP, however I would like to use a more tested solution like WAMP. On top of that, I want to place a quite heavy WordPress / BuddyPress installation (that I hope will bring a lot of trafic :)
Has anyone done something similar to this? If so, what is your experience / pitfalls etc.?
Thanks
Stelios
Yes, you can do this. At the end of the day you are just using Windows Server, so anything that installs there will install in the cloud as well. I have done this myself for hosting WordPress in Windows Azure.
However, there are some pitfalls here. Mostly the pitfalls are around the M (MySQL). To setup MySQL in Windows Azure is not really that hard, but you have several considerations on how to make sure it is always available. You can:
Setup a single instance of MySQL in
a role and store the db on local
disk (this is a bad idea).
Setup a single instance of MySQL in
a role and store the db on a drive
(blob backed storage)
Setup 2 instances of MySQL to each
point to a shared drive
(hot-failover). Only one drives will
be able to mount. Now, you have reliability and failover, but a single instance at a time working for you.
Setup 1 writer of MySQL on a drive,
and multiple readers on a snapshot
of a drive. Put in some logic via
connection strings to make sure only
writes goto a single one and reads
to the others. Snapshot every X
mins to update readers.
Setup multiple instances of MySQL
and use native replication features
(each storing to local disk) and
rely on that if you lose an
instance.
There are probably more permutations, but the gist of the problem is how you scale out MySQL to be available and reliable. In Windows Azure, you don't get to rely on the fact that the local disk will always be around or that you will always have the same instance. In fact, you can guarantee that your instances will be down for some period of time each month and eventually, given enough time, you will lose the local disk.
Overall, with multiple instances however, you can guarantee they won't be down simultaneously (to the service SLA level at least). So, you need to make sure MySQL works with multiple instances (or live with single instance downtime) and that your data is backed by blob storage to guarantee it is persisted.
Or you can scrap all that crap and just use SQL Azure, which solves all those problems. So, it become WASP. SQL Azure can also be more economical as well for smaller DBs.
Or you can scrap all that crap and just use SQL Azure, which solves all those problems. So, it become WASP. SQL Azure can also be more economical as well for smaller DBs.
Ditto.
Installing MySQL on an Azure role is not a good idea for plenty of reasons, most notably (lack of) scalability and reliability. (That's just for deploying on Azure, MYSQL itself is great)
To set it up remotely reliably you're going to need a dedicated instance which will run you at least $40 a month, going with SQL Azure is $10/Gb, or free if you get an introductory offer or Bizspark.
If you're just looking to play around with a single instance app, I'd suggest you rather use SQLite or some other in memory db, it'll be a lot less painful.
I intend to start developing an ASP.NET application and I am wondering which database to use. Performance is very important and the database should be able to handle without issues a database of about 50GB. I am wondering however, if a SQL Server license is worth paying for. I have looked for performance and scalability comparisons between MSSQL Server (2005/2008) and MySQL but I can't seem to find any good tests. Can you point me to some extensive benchmarks related to this subject?
MySQL traditionally is very fast if you are doing a lot of reads. For example in a web site there is probably a 100 to 1 read write ratio so MySQL works well. If you are planning a high transaction database then head straight to MSSQL. If money is no issue head straight to MSSQL anyway because it is a better product.
As mentioned, MySQL can provide high read performance (assuming simple queries with few or no joins) as long as you use the default table type.
However you also stated the database is 50GB in size, which suggests you may be looking for a database that will reliably store the information. Using the default table type MySQL is not a reliable database by any stretch of the imagination.
If you want a fast, free alternative to MS SQL then PostgreSQL may be a good choice - it is fast reliable, and has a more open licence (if you use MySQL for a commercial project you'll want to read its dual licence very carefully). The only downside to PostgreSQL is that it shares some of the same DBA guru requirements as Oracle, where as MS SQL can often be managed by a regular IT person, and MySQL doesn't need much management besides restoring the old backups everytime it decides to become corrupted and lose your data.
I don't know how authoritative this is but I found this:
http://www.sqlite.org/cvstrac/wiki?p=PerformanceConsiderations
and it doesn't seem good to have a lot of connections to sqlite. This seems to be bad for the web and most applications that have more than a few users. I'm having a hard time thinking of what sqlite would be used for when you don't need that many connections. Every program I can think of needs users, lots of them sometimes, so what would I use a database for that doesn't allow that many connections? I thought about prototypes but why would I use that when I can just connect to a larger database? Embedded apps maybe?
Thank you.
EDIT: Thanks everyone. I look at the page recommended below but an confused about something:
Under appropriate uses for sqlite it has:
Situations Where SQLite Works Well
•Websites
SQLite usually will work great as the database engine for low to medium traffic websites (which is to say, 99.9% of all websites). The amount of web traffic that SQLite can handle depends, of course, on how heavily the website uses its database. Generally speaking, any site that gets fewer than 100K hits/day should work fine with SQLite. The 100K hits/day figure is a conservative estimate, not a hard upper bound. SQLite has been demonstrated to work with 10 times that amount of traffic.
Situations Where Another RDBMS May Work Better
•Client/Server Applications
If you have many client programs accessing a common database over a network, you should consider using a client/server database engine instead of SQLite. SQLite will work over a network filesystem, but because of the latency associated with most network filesystems, performance will not be great. Also, the file locking logic of many network filesystems implementation contains bugs (on both Unix and Windows). If file locking does not work like it should, it might be possible for two or more client programs to modify the same part of the same database at the same time, resulting in database corruption. Because this problem results from bugs in the underlying filesystem implementation, there is nothing SQLite can do to prevent it.
A good rule of thumb is that you should avoid using SQLite in situations where the same database will be accessed simultaneously from many computers over a network filesystem.
The Question:
I'm going to show my ignorance here but what is the difference between these two?
This is answered well by sqlite itself : Appropriate use of sqlite
Another way to look at SQLite is this:
SQLite is not designed to replace Oracle. It is designed to replace fopen().
It's good for situations where you don't have access to a "real" database and still want the power of a relational db. For example, Firefox stores a bunch of information about your settings/history/etc in an SQLite database. You can't expect everyone that runs firefox to have MySQL or postgre installed on their machine.
It's also perfectly capable of running relatively-low traffic, read-heavy websites. The performance of it is overall very good, it's more than the large majority of websites need for their traffic levels.
It's often used for embedded applications.
It can be very handy to use a database like storage when you have no access to a database service. So SQLite is used since it's just a file you store somewhere.
I also find that using SQLite is good for getting a prototype application together pretty quickly without the overhead of having a seperate DB server or bogging a development environment with an instance of MySQL/Oracle/Whatever.
Also easy to pick up and move the database to a different machine if you need to.
The iPhone uses it for call history, SMS messages, contacts, and other type of data. Like Ólafur Waage said, good for embedded applications on mobile device because it's lightweight. I have used it also on stand alone applications. Easy to use and available on most platforms.
Think about simple client or desktop apps that could make use of a db, like as a poor example, an address book. Rather than bundling a huge db engine like mysql or postgre with your deliverable, sqlite is very lightweight and easy to include with your finished app.
This FLOSS Weekly podcast episode talks with the creator of SQLite and covers among other things goes over the type of things you would use it for. Everything from file systems for mobile phones to smallish web sites.
In the simplest terms, SQLite is a public-domain software package that provides a
relational database management system, or RDBMS. Relational database systems are
used to store user-defined records in large tables. In addition to data storage and management,
a database engine can process complex query commands that combine data
from multiple tables to generate reports and data summaries. Other popular RDBMS
products include Oracle Database, IBM’s DB2, and Microsoft’s SQL Server on the
commercial side, with MySQL and PostgreSQL being popular open source products.
The “Lite” in SQLite does not refer to its capabilities. Rather, SQLite is lightweight
when it comes to setup complexity, administrative overhead, and resource usage.
For detail info and solution about SQLite visit the link below:
http://blog.developeronhire.com/what-is-sqlite-sqlite/
Thank you.
What the above two answers say. Expanding slightly on Chad Birch's answer, its teh calls to the SQLite db, and a rather poor implementation of sync() that causes FF3 to be so slow in linux.
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I recently read this Question about SQLite vs MySQL and the answer pointed out that SQLite doesn't scale well and the official website sort-of confirms this, however.
How scalable is SQLite and what are its upper most limits?
Yesterday I released a small site* to track your rep that used a shared SQLite database for all visitors. Unfortunately, even with the modest load that it put on my host it ran quite slowly. This is because the entire database was locked every time someone viewed the page because it contained updates/inserts. I soon switched to MySQL and while I haven't had much time to test it out, it seems much more scaleable than SQLite. I just remember slow page loads and occasionally getting a database locked error when trying to execute queries from the shell in sqlite. That said, I am running another site from SQLite just fine. The difference is that the site is static (i.e. I'm the only one that can change the database) and so it works just fine for concurrent reads. Moral of the story: only use SQLite for websites where updates to the database happen rarely (less often than every page loaded).
edit: I just realized that I may not have been fair to SQLite - I didn't index any columns in the SQLite database when I was serving it from a web page. This partially caused the slowdown I was experiencing. However, the observation of database-locking stands - if you have particularly onerous updates, SQLite performance won't match MySQL or Postgres.
another edit: Since I posted this almost 3 months ago I've had the opportunity to closely examine the scalability of SQLite, and with a few tricks it can be quite scalable. As I mentioned in my first edit, database indexes dramatically reduce query time, but this is more of a general observation about databases than it is about SQLite. However, there is another trick you can use to speed up SQLite: transactions. Whenever you have to do multiple database writes, put them inside a transaction. Instead of writing to (and locking) the file each and every time a write query is issued, the write will only happen once when the transaction completes.
The site that I mention I released in the first paragraph has been switched back to SQLite, and it's running quite smoothly once I tuned my code in a few places.
* the site is no longer available
Sqlite is scalable in terms of single-user, I have multi-gigabyte database that performs very well and I haven't had much problems with it.
But it is single-user, so it depends on what kind of scaling you're talking about.
In response to comments. Note that there is nothing that prevents using an Sqlite database in a multi-user environment, but every transaction (in effect, every SQL statement that modifies the database) takes a lock on the file, which will prevent other users from accessing the database at all.
So if you have lots of modifications done to the database, you're essentially going to hit scaling problems very quick. If, on the other hand, you have lots of read access compared to write access, it might not be so bad.
But Sqlite will of course function in a multi-user environment, but it won't perform well.
SQLite drives the sqlite.org web site and others that have lots of traffic. They suggest that if you have less than 100k hits per day, SQLite should work fine. And that was written before they delivered the "Writeahead Logging" feature.
If you want to speed things up with SQLite, do the following:
upgrade to SQLite 3.7.x
Enable write-ahead logging
Run the following pragma: "PRAGMA cache_size = Number-of-pages;" The default size (Number-of-pages) is 2000 pages, but if you raise that number, then you will raise the amount of data that is running straight out of memory.
You may want to take a look at my video on YouTube called "Improve SQLite Performance With Writeahead Logging" which shows how to use write-ahead logging and demonstrates a 5x speed improvement for writes.
Sqlite is a desktop or in-process database. SQL Server, MySQL, Oracle, and their brethren are servers.
Desktop databases are by their nature not a good choices for any application that needs to support concurrent write access to the data store. This includes at some level most web sites ever created. If you even have to log in for anything, you probably need write access to the DB.
Have you read this SQLite docs - http://www.sqlite.org/whentouse.html ?
SQLite usually will work great as the
database engine for low to medium
traffic websites (which is to say,
99.9% of all websites). The amount of web traffic that SQLite can handle
depends, of course, on how heavily the
website uses its database. Generally
speaking, any site that gets fewer
than 100K hits/day should work fine
with SQLite. The 100K hits/day figure
is a conservative estimate, not a hard
upper bound. SQLite has been
demonstrated to work with 10 times
that amount of traffic.
SQLite scalability will highly depend on the data used, and their format. I've had some tough experience with extra long tables (GPS records, one record per second). Experience showed that SQLite would slow down in stages, partly due to constant rebalancing of the growing binary trees holding the indexes (and with time-stamped indexes, you just know that tree is going to get rebalanced a lot, yet it is vital to your searches). So in the end at about 1GB (very ballpark, I know), queries become sluggish in my case. Your mileage will vary.
One thing to remember, despite all the bragging, SQLite is NOT made for data warehousing. There are various uses not recommended for SQLite. The fine people behind SQLite say it themselves:
Another way to look at SQLite is this: SQLite is not designed to replace Oracle. It is designed to replace fopen().
And this leads to the main argument (not quantitative, sorry, but qualitative), SQLite is not for all uses, whereas MySQL can cover many varied uses, even if not ideally. For example, you could have MySQL store Firefox cookies (instead of SQLite), but you'd need that service running all the time. On the other hand, you could have a transactional website running on SQLite (as many people do) instead of MySQL, but expect a lot of downtime.
i think that a (in numbers 1) webserver serving hunderts of clients appears on the backend with a single connection to the database, isn't it?
So there is no concurrent access in the database an therefore we can say that the database is working in 'single user mode'. It makes no sense to diskuss multi-user access in such a circumstance and so SQLite works as well as any other serverbased database.
Think of it this way. SQL Lite will be locked every time someone uses it (SQLite doesn't lock on reading). So if your serving up a web page or a application that has multiple concurrent users only one could use your app at a time with SQLLite. So right there is a scaling issue. If its a one person application say a Music Library where you hold hundreds of titles, ratings, information, usage, playing, play time then SQL Lite will scale beautifully holding thousands if not millions of records(Hard drive willing)
MySQL on the other hand works well for servers apps where people all over will be using it concurrently. It doesn't lock and it is quite large in size. So for your music library MySql would be over kill as only one person would see it, UNLESS this is a shared music library where thousands add or update it. Then MYSQL would be the one to use.
So in theory MySQL scales better then Sqllite cause it can handle mutiple users, but is overkill for a single user app.
SQLite's website (the part that you referenced) indicates that it can be used for a variety of multi-user situations.
I would say that it can handle quite a bit. In my experience it has always been very fast. Of course, you need to index your tables and when coding against it, you need to make sure you use parameritized queries and the like. Basically the same stuff you would do with any database to improve performance.